At this stage, the anterior mesodermal precursor resembles a large mass of cells in front of and on both sides of the archenteron.
These observations demonstrate that with a pregnancy preexisting premalignant mammary cells overcome both the apoptotic response to an oncoprotein and the robust cell death at involution, which normally clears the large mass of cells gained during pregnancy/lactation.
Some of the old polypide is recycled, but much of it remains as a large mass of dying cells containing accumulated wastes, and this is compressed into a "brown body".
Interestingly, certain tumors are highly resistant to chemotherapy and other forms of treatment and although aggressive treatments destroy the majority of the cancerous cells, a small fraction of the cells survive and often regenerate into even larger masses of tumor cells [22], [23], [24].
Although aggressive treatments can destroy the majority of the cancerous cells, a small fraction of them remain and often later regenerate into even larger masses of tumor cells that are even more treatment resistant [17], [18], [20].
However, a large mass of islet cell sheets is required for the subcutaneous transplantation to reverse hyperglycemia in diabetic mice.
Lenses lacking both Acvr1 and Trp53 had large confluent masses of cells at their posterior pole (Fig. 7D).
The comedo cancer is a poorly differentiated ductal cancer, which is rich in mitoses, often with large intraductal masses of cells with central necroses (comedons).
This, of course, only created a large mass of small armed cells that tore the whole system down.
